The present invention relates to the art of drilling, particularly rock drilling, by means of drilling machines, in particular drilling hammers. For the drilling of holes of different diameters, drills of different diameters must be used, the different chucking shanks of which must be capable of being chucked in one and the same tool holder, insofar as possible. In this connection, the problem arises that, despite the different force exerted on the tool holder when drilling holes of different diameters, the drills must in all cases be dependably driven by the tool holder and disturbances must be avoided insofar as possible. In the case of hammer drills there is also the additional problem that the chucking shanks of the drills, when the blows are exerted on the end surface of the chucking shank, must be properly guided axially in the tool holder without being pushed out, even in the case of extremely thick or thin chucking shanks.
From Federal Republic of Germany, No. OS 3,118,691, there is known a tool holder for drilling hammers which, for the chucking of chucking shanks of drills of different thickness, has at least two jaws for which a jaw holder is present which is provided with a hollow space for receiving the chucking shanks to be chucked and into which, upon the clamping fast of the chucking shanks, the jaws, which are mounted radially insertable and lockable in the jaw holder, engage via their drives.